Process and apparatus of ocean carbon capture and storage

ABSTRACT

The present invention relates to a process and an apparatus of ocean carbon capture and storage (Ocean CCS), which can be used for carrying out carbon capture and storage of flue gas discharged from marine facilities using fossil energy such as coastal power plants and marine ships, and direct air capture (DAC). The natural engineering method are adopted in the present invention, and natural seawater is used for washing and dissolving CO 2  gas for carbon capture; and natural seawater carbonate neutralization and formed bicarbonate is used for ocean storage in water column; and low head and large water flow is used to save energy. The discharged water complies with environmental regulations. The present invention provides an affordable and green effective mean for using marine ecosystems of carbon sinks and reservoirs to respond to the climate change.

RELATED APPLICATIONS

The present application is Divisional of U.S. application Ser. No.15/568,596, filed Oct. 23, 2017, which is a National Phase ofInternational Application Number PCT/CN2017/087530, filed Jun. 8, 2017,and claims the priority of China Application No. 201710137942.8, filedMar. 9, 2017 and China Application No. 201610408323.3, filed Jun. 11,2016.

FIELD OF THE INVENTION

The present invention relates to a process and an apparatus of oceancarbon capture and storage (Ocean CCS), applicable to carbon dioxidecapture and storage for coastal power plants, marine ships and othermarine facilities burning fossil fuels and/or direct air capture (DAC).The present invention belongs to a technical field of clean energy andearth engineering.

DESCRIPTION OF RELATED ART

Capture and storage of the carbon dioxide, namely CCS, is a necessarytechnical solution to reduce greenhouse gases in the atmosphere.However, all of the existing CCS arts are costly geological storagepolicies, which are far from the actual application from the economicaland affordable aspects. Large-scale emission reduction is hard to beachieved.

According to the earth science theory, the absorption of the extracarbon dioxide in the atmosphere depends on the water column of deepocean finally. For this reason, big studies by internationalinstitutions further show that the oceans are already naturallyabsorbing CO₂ from the atmosphere at a rate of about 6 Gt/y and the CO₂flows to the deep ocean naturally. International studies also show thatcarbon dioxide is a naturally occurring product and its overall impacton the ocean environment should be very small, because of the large sizeof the ocean carbon reservoir (many times larger than the terrestrialreservoir) (IEA OCEAN STORAGE OF CO₂). The conclusion of these studiesis that ocean carbon storage is the most cost-effective and prospectivepolicy to respond to the climate change, which is also the safest andthe most effective. For this reason, tests of ocean carbon storage werefurther carried out in 2001. They are going to inject liquid carbondioxide into two ocean areas in Hawaii and Norway. However, the testswere banned finally though all preparations for funds and materials(including 60 t of liquid carbon dioxide) were made, becauseenvironmental protection agency pointed out that injection of CO₂ inform of liquid, dense gas or solid into the ocean will lead to immediatedeath of marine, which seriously destroy the ecological environment ofthe injected area. Therefore, the test belongs to “marine dumping”behaviors prohibited by the London Convention and OSPAR Convention.Since then, the international experimental research on ocean carbonstorage has stagnated for over a decade. Therefore, tests of oceanstorage cannot be carried out in the ocean if the storage mode ofhigh-concentration carbon dioxide of the geological storage is usedcontinuously. So, the benefit of “the most cost-effective policy” cannotbe demonstrated and applied, and ocean storage cannot become a practicalpolicy for carbon reduction. Finally, the long-time desire forresponding to the climate change effectively using ocean resourcescannot be achieved.

SUMMARY OF THE INVENTION

The purpose of the process and apparatus of ocean carbon capture andstorage of the invention is to overcome the defect of the prior art ofocean carbon storage, and to provide the most cost-effective policy ofocean carbon storage which also comply with environmental regulations,so that the ocean carbon storage can be practical solution to respond tothe climate change. Meanwhile, the solution is affordable from theeconomic and environmental aspects.

The present invention firstly provides a process of ocean carbon captureand storage, comprising steps of:

-   -   1) carbon capture including scrubbing gas containing carbon        dioxide with pumped seawater to produce after-scrubbing seawater        as a product of carbon capture in which the carbon dioxide of        the gas is absorbed; and    -   2) carbon storage including discharging the product of carbon        capture into the water column of ocean to realize ocean storage.

In a preferred embodiment, in step 2), the product of carbon capture isdischarged into the water column of ocean under atmospheric pressurethrough a pipe.

In a preferred embodiment, the process further comprises adjusting aratio of volume of the seawater to volume of carbon dioxide in theproduct of carbon capture to adjust pH value of the product of carboncapture discharged into the ocean.

In a preferred embodiment, the gas containing carbon dioxide in step 1)is atmosphere, and the seawater for scrubbing is pumped with powerprovided by wind, and/or wave of ocean current, and/or sunlight.

In a preferred embodiment, the gas containing carbon dioxide is flue gasdischarged from burning of fossil fuel.

In a preferred embodiment, the process further comprises the steps thatat least 10%, or 20%, or 50%, or 70%, or 80%, or 90% of the carbondioxide in the flue gas is absorbed into the seawater and then isdischarged into the water column of ocean, and a volume of the seawateris configured to be enough to absorb at least 10%, or 20%, or 50%, or70%, or 80%, or 90% of the carbon dioxide of the flue gas.

In a preferred embodiment, the process further comprises the step thatthe seawater is pumped to a head of no more than 50 m, or 40 m, or 30 m,or 20 m, or 19 m, or 15 m, or 12 m, or 10 m, or 9 m, or 8 m, or 6 m, or5 m, or 4 m, or 2 m, or 1 m to scrub the flue gas containing carbondioxide, wherein the head of 0 m is a level of ocean where the scrubbingseawater is pumped.

In a preferred embodiment, the process further comprises providingpackings and performing the scrubbing in the packings and configuring ahead of the pumped scrubbing seawater so that an energy consumption ofthe carbon capture is no more than 1000 MJ/t, or 500 MJ/t, or 400 MJ/t,or 350 MJ/t, or 300 MJ/t, or 250 MJ/t, or 200 MJ/t, or 150 MJ/t, or 100MJ/t, or 60 MJ/t, or 50 MJ/t, or 40 MJ/t, or 30 MJ/t, or 20 MJ/t, or 10MJ/t, or 5 MJ/t.

In a preferred embodiment, a whole process from the carbon capture tothe carbon storage is a consecutive reaction.

In a preferred embodiment, the process further comprises discharging theproduct of carbon capture into the surface layer, and/or the middlelayer, and/or the deep layer of the water column of ocean.

In a preferred embodiment, the process further comprises discharging theafter-scrubbing seawater into an ocean current in the water column ofocean that does not pass the location where the scrubbing seawater ispumped.

In a preferred embodiment, the packing scrubbing is realized throughlarge area contact between the scrubbing seawater and the flue gas.

The present invention secondly provides a process of ocean carboncapture and storage, wherein the process comprises the steps of:

a. continuously leading flue gas containing carbon dioxide which isdischarged from a burner for burning fossil fuel into a carbon capturedevice;

b. continuously leading seawater into the carbon capture device;

c. providing packings in the carbon capture device to enlarge contactarea of the flue gas of step a and the seawater of step b to scrub theflue gas and absorb the carbon dioxide of the flue gas;

d. continuously discharging scrubbed flue gas into atmosphere, whereinin the scrubbed flue gas, the volume of carbon dioxide has reduced;

e. continuously discharging the seawater containing carbon dioxidegenerated in step c from the carbon capture device; and

f. continuously discharging the seawater containing carbon dioxidegenerated in step e into a carbon storage location in an ocean torealize the carbon storage;

wherein the fossil fuel is selected from a group consisting of coal, oiland gas; and the burner is selected from a group consisting of a boilerof a steam turbine, an internal combustion engine and a gas turbinewhich are used in a coastal power plant or a marine ship; and the fluegas is generated from burning of the fossil fuel; and the seawater ofstep b is the seawater pumped from the ocean to be used for scrubbingdirectly, and/or is the seawater pumped from the ocean to cool theburner firstly before being used for scrubbing.

In a preferred embodiment, at least 10%, or 20%, or 50%, or 70%, or 80%,or 90% of carbon dioxide in flue gas in step a is removed compared withthe scrubbed flue gas in step d.

In a preferred embodiment, at least 20% of carbon dioxide in flue gas instep a is removed compared with the scrubbed flue gas in step d.

In a preferred embodiment, the difference between the increasedtemperature of the seawater containing carbon dioxide dischargedcontinuously in step e and the temperature of the seawater led into thecarbon capture device in step b, is less than 50° C.

In a preferred embodiment, the difference between the increasedtemperature of the seawater containing carbon dioxide dischargedcontinuously in step e and the temperature of the seawater led into thecarbon capture device in step b, is less than 20° C.

In a preferred embodiment, the difference between the increasedtemperature of the seawater containing carbon dioxide dischargedcontinuously in step e and the temperature of the seawater led into thecarbon capture device in step b, is less than 2° C.

In a preferred embodiment, the difference between the decreased pH valueof the seawater containing carbon dioxide discharged continuously instep e and the pH value of the seawater at carbon storage location is nomore than 2 pH unit.

The present invention thirdly provides an apparatus of ocean carboncapture and storage, comprising:

-   -   a burner for producing the flue gas from the burning of fossil        fuel;    -   a carbon capture device, which is connected to the burner to        scrub the flue gas to capture carbon dioxide;    -   a seawater pumping equipment for leading seawater into the        carbon capture device;    -   a chimney for leading cleaned flue gas out of the carbon capture        device; and    -   a seawater discharging pipe;        wherein the carbon capture device comprises a water distributor        and a packing layer; and a seawater outlet of the carbon capture        device is connected to the seawater discharging pipe; and a        outlet of the discharging pipe is located in the water column of        ocean.

In a preferred embodiment, an altitude of the water distributor of thecarbon capture device is configured to be no more than 50 m, or 40 m, or30 m, or 20 m, or 19 m, or 15 m, or 12 m, or 10 m, or 9 m, or 8 m, or 6m, or 5 m, or 4 m, or 2 m, or 1 m, wherein the altitude of the waterdistributor is defined by a distance between a horizontal centre of thewater distributor and level of ocean where the scrubbing seawater ispumped into the seawater pumping equipment.

In a preferred embodiment, the seawater pumping equipment of the carboncapture device is a seawater cooling system for the burner and/or aseawater intake pump.

In a preferred embodiment, the apparatus further comprises a seawateradjusting pump which is connected to a water regulator to adjust pHvalue of the scrubbing seawater discharged into the ocean.

In a preferred embodiment, the packing layer of the carbon capturedevice is composed of industrial bulk packings, and/or regular packings,and/or perforated plate packings, and/or grilles.

In a preferred embodiment, a dry packing factor of the packing is5˜2000/m, wherein the definition of the dry packing factor is accordingto the manual of conventional packing industrial products.

In a preferred embodiment, the seawater discharging pipe is a membranepipe.

In a preferred embodiment, the carbon capture device is located on anocean platform which has an adjustable altitude according to level oftide.

The present invention fourthly provides an apparatus of ocean carboncapture and storage for carrying out the process of the presentinvention, comprising:

-   -   a carbon capture device;    -   a seawater pumping equipment for leading seawater into the        carbon capture device; and    -   a power equipment for providing power for the seawater pumping        equipment;    -   a water distributor which is over the carbon capture device;    -   a water collector which is under the carbon capture device; and    -   a seawater discharging pipe which is connected to the water        collector.

In a preferred embodiment, the power equipment comprises a wind powerdevice, and/or a conversion device of wave of ocean current, and/or asolar power device.

In a preferred embodiment, the power equipment comprises:

-   -   a wind driven device;    -   a power transmission device which is connected to the seawater        pumping equipment to transmit the power provided by the wind        driven device to the seawater pumping equipment;    -   wherein the power transmission device comprises a mechanical        transmission device and/or a electromechanical transmission        device composed of a wind driven generator and an electromotor.

In a preferred embodiment, the energy equipment comprises:

-   -   a water driven device;    -   a power transmission device which is connected to the seawater        pumping equipment to transmit the power provided by the water        driven device to the seawater pumping equipment;

wherein the power transmission device comprises a mechanicaltransferring device and/or a electromechanical transmission devicecomposed of a water driven generator and electromotor.

In a preferred embodiment, the above two apparatus for carrying out theprocess of the present invention is fixed on a seabed and/or oceanplatform.

The following description is to set forth the technical principle andeffect of the present invention.

The principle used in the present invention is that carbon dioxide is anatural substance soluble in seawater and abundant in seawater, and thestorage of carbon dioxide in ocean can be massive and long-term andenvironment-friendly. In the present invention, flue gas discharged fromfossil fuel is scrubbed by seawater, or the atmosphere (i.e. the air inits natural state) is collected and scrubbed directly to achieve thepurpose of carbon capture through the dissolution of carbon dioxide inthe flue gas and/or atmosphere, and then the seawater in which carbondioxide in the flue gas and/or atmosphere is dissolved is discharged tothe surface layer, and/or middle layer, and/or deep layer of the watercolumn in the ocean to achieve the purpose of carbon storage under theconditions that the related indicators such as pH value comply withenvironmental regulations. Moreover, the diffusion of the ocean currentcan further reduce the harmful impact on the marine environment, andfurther enhance the effect of ocean storage. The seawater in whichcarbon dioxide is dissolved can be discharged to the surface layer, ormiddle layer, or deep layer of the water column in the sea or ocean.Some other studies indicate that the CO₂ can be stored for 1000 years ifit is discharged to a depth of 1000 m in the ocean.

CO₂ is dissolved in seawater according to the response of followingequation (from left to right):CO₂+H₂O⇔H₂CO₃(carbonic acid)H₂CO₃⇔H⁺+HCO₃ ⁻(bicarbonate ion)HCO₃ ⁻⇔H⁺+CO₃ ²⁻(carbonate ion)

The bicarbonate ion is the main form of carbon dioxide in seawater. Thecarbonic acid, bicarbonate ion and carbonate ion are collectivelyreferred to as dissolved inorganic carbon (DIC).

Usually the solubility of carbon dioxide in water is very low, so theseawater scrubbing produces a low concentration of CO₂, namely theafter-scrubbing seawater which contains a low concentration of DIC. Thewording of “low concentration” should be read as compared with the priorart. In the prior art, the product of carbon capture is in form of apure liquid carbon dioxide, dense gas or solid, in which theconcentration of carbon dioxide is several orders of magnitude higherthan that in the present invention. A person skilled in the art mayconsider that the energy consumption is very huge in the presentinvention because massive scrubbing seawater is needed due to the “lowconcentration”. However, in the present invention, the total energyconsumption can be reduced by reducing the pumping head of the seawater,so that the cost of carbon capture and storage is at least an order ofmagnitude lower than that of the prior CCS art. In coastal thermal powerplant, the cost can be further reduced if cooling water is reused.

At the same time, the present invention has the effect of flue gasdesulfurization because sulfur dioxide is also a kind of naturalsubstance soluble and abundant in seawater, and sulfur dioxide in theflue gas is less than that of carbon dioxide, and sulfur dioxide is moresoluble in water than carbon dioxide. Therefore, the present inventionhas also an effect of flue gas desulfurization.

Obviously, the application of the present invention can up-scale thecommercial application of carbon capture and storage in the coastalareas where large carbon emission sources are located densely. In suchcondition, scale effect is prominent.

Double effects can be achieved if the present invention is applied inocean shipping. The first one is that the carbon sink resources of thesurface layer of ocean can be used so that the escaped carbon emissionswhich cannot be captured previously can be captured and kept in storagecurrently, which reduces the carbon emissions from ships at extremelylow cost. The second one is to avoid using low sulphur fuel, indirectlyreducing carbon emissions of oil refining industry. Therefore, the dualpressure under the international carbon reduction, sulfur reduction actcan be released in shipping industry. Economic and green advantages canbe maintained continuously.

There are especially important benefits if carbon capture and storage ofthe present invention is used for the air in its natural condition. Thefirst reason is that the atmospheric circulation can be used forcapturing all kinds of carbon emissions without transport cost,including the escaped carbon emissions which cannot be captured by othermethods. The second one is that carbon capture and storage with zeroenergy consumption can be realized by using wind, ocean current,sunshine and other renewable energy. The third reason is that there isno limit on ocean area and peripheral supports are not needed so that alarge number of apparatuses can be fixed in all kinds of ocean area.

Obviously, the present invention based on the earth science principle,has achieved good technical effects by adopting the method of naturalengineering. The present invention provides an affordable and practicaland effective technical policy for achieving the long-time desire ofusing ocean resources to respond to the climate change.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of the implementationsteps of the process of seawater carbon capture and storage of thepresent invention.

FIG. 2 is a schematic diagram showing another example of theimplementation steps of the process of seawater carbon capture andstorage of the present invention.

FIG. 3 is a schematic diagram showing an example of the presentinvention used in a coastal gas-steam combined cycle power plant.

FIG. 4 is a schematic diagram showing another example of the presentinvention used in a coastal coal-fired power plant.

FIG. 5 is a schematic diagram showing an example of a marine ship of thepresent invention.

FIG. 6 is a schematic diagram showing an example of water driven carboncapture and storage of atmosphere on ocean of the present invention.

FIG. 7 is a schematic diagram showing an example of wind driven carboncapture and storage of atmosphere on ocean of the present invention.

Names of components or structures corresponding to the reference numbersin the drawings are provided as follows.

1—burner; 2—carbon capture device; 2.1—water distributor; 2.2—altitudeof water distributor; 2.3 water collector; 3—seawater pumping equipment;3.1—seawater increase pump; 3.2—level of ocean; 4—seawater adjustingpump; 5—seawater outlet; 6—chimney; 7—seawater discharging pipe; 8—waterregulator; 9—sea chest; 10—main seawater duct of ship; 11—cabin,12—coast; 13—ocean current; 14—power equipment; 14.1—wind driven device;14.2—water driven device; 14.3—power transmission device; 15—wind.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a process of ocean carbon capture andstorage, comprising steps of:

1) carbon capture including scrubbing gas containing carbon dioxide withpumped seawater to produce after-scrubbing seawater as a product ofcarbon capture in which the carbon dioxide of the gas is absorbed; and

2) carbon storage including discharging the product of carbon captureinto the water column of ocean.

The term of “seawater” here should be read as natural seawater derivedfrom the sea or ocean, including the natural seawater for coolingindustrial facilities. The purpose of the present invention can beachieved by using the seawater without adding any other substance (e.g.,adding alkali). Of course, in some applications, other additives canalso be added to achieve special purposes, such as, in order to absorbsome special components in the flue gas.

The term of “scrubbing” here should be read as the step of contact ofseawater with the gas for the purpose of carbon dioxide capture. Contactcan be performed in an apparatus including but not limited to: sprayinjector, bubbler, Venturi tower, sprayer, filter, rotary sprayer,grille, trays tower or packing tower.

The wording of “carbon capture” here should be read as the step ofcapturing CO₂ in the gas containing carbon dioxide in the course ofscrubbing. In the course of scrubbing, some of the CO₂ is dissolved intothe seawater to be a dissolved inorganic carbon (DIC) in theafter-scrubbing seawater.

The wording of “carbon storage” here should be read as the step ofdischarging the after-scrubbing seawater containing CO₂ of the flue gasinto the water column of ocean directly under atmospheric pressurethrough pipes. In the course of carbon storage, concentrated CO₂ is notneeded before discharged. If needed, further dilution of CO₂ can beperformed by adding additional seawater to adjust the pH value ofdischarged seawater to comply with environmental regulations. Differentrequirements on the pH value of discharged seawater may be needed indifferent regions of the ocean, including different depths of the ocean.

The wording of “water column of ocean” here should be read as theseawater in the surface layer (tens of meters of depth), the middlelayer (less than hundreds of meters of depth) or deep layer (more thanhundreds of meters of depth). International Studies by IPCC and IEA showthat the physical and chemical systems of water column of ocean, as wellas the marine ecosystem, can absorb and store carbon dioxide friendly.

The flowing seawater, i.e. the ocean current can enhance the effect ofocean carbon storage. If the product of carbon capture is dischargedinto the ocean current of the water column of ocean that does not passthe inlet through which the scrubbing seawater is pumped, it can preventthe discharged seawater from flowing back to the inlet.

These are common knowledge that CO₂ is soluble in water and the seawatercan absorb more CO₂. But so far, there is no report on any technicalpolicy that seawater is used for carbon capture and storage. The reasonis that the people skilled in the art are accustomed to considering thatthe only way to reduce cost to be affordable is purifying the capturedCO₂ into high concentration in a form of liquid, dense gaseous or solidto reduce material volume to reduce the cost of transportation andstorage. Because the cost of the high-concentration solution is far froman affordable and practical technology, it is not possible of a personskilled in the art to think of any low-concentration policy.

The inventor of the present invention has been engaged in research ondesulfurization by seawater scrubbing for a long time. The inventoraccidentally found that the low-concentration solution of seawaterscrubbing brings the effects of not only desulfurization, but alsocarbon capture and storage. Moreover, the inventor also found a methodto greatly reduce costs, so that the cost is reduced to be affordableand practical.

What the invention of the present invention found firstly is that, inthe prior technology of desulfurization of seawater scrubbing (FGD,EGC), less than 10% of the carbon dioxide in flue gas are usuallydissolved into the scrubbing water, and they were driven into theatmosphere in the process of drainage and aeration treatment. Therefore,the inventor of the present invention carried out a test on FGD in acoastal power plant and a test on EGC in an ocean tanker for many years.The tests indicated it is possible that carbon dioxide dissolved in theseawater is not driven out or a small amount of carbon dioxide dissolvedin the seawater is driven out under the condition that the dischargedseawater complies with the environmental regulations, if the technologyof desulfurization of seawater scrubbing is modified properly.

The inventor of the present invention also found in a further test thatincreasing the volume of scrubbing seawater can result in that more than10% of the carbon dioxide in the flue gas is captured and kept instorage. The inventor also found that the energy consumption and thecost, which increase in the course of increasing the volume of scrubbingseawater, can be reduced through a method of reducing the head ofscrubbing seawater which is pumped. In this case, the cost for captureand storage of at least 20% of the carbon dioxide in the flue gas isusually affordable in a variety of applications, such as power plantsand ships. The following part of the present application provides adetailed description of several examples that the cost for removing morecarbon dioxide is affordable in several typical applications. In theseexamples, the purpose that no less than 30%, or 40%, or 50%, or 60%, or70%, or 80%, or 90% of carbon dioxide in the flue gas is captured andkept in storage is finally achieved. In an example of coastal powerplant, even 99% of CO₂ in the flue gas is captured and kept in storage,and the increased cost is affordable.

Because a certain amount of water can dissolve limited amount of CO₂(generally 1 m³ of freshwater can absorb about 0.8 m³ of CO₂ under roomtemperature and atmospheric pressure, and the seawater can absorb alittle more CO₂ than freshwater), a large amount of scrubbing seawateris needed if a large number of CO₂ from flue gas is needed to becaptured. For example, in an example of power plant, if all of theoriginal cooling seawater is used to scrub flue gas, only about 30% ofCO₂ can be captured. If more than 90% of CO₂ is needed to be captured,it is needed to add additional scrubbing seawater in amount that isabout twice original cooling seawater. Generally speaking, it is a veryhuge amount. For the purpose of affordable cost, it is needed to adopttwo technical strategies. The one is to reduce the energy consumption ofpumping seawater, and the other is to increase the absorption efficiencyof seawater to CO₂ to minimize the amount of scrubbing seawater which isneeded. Firstly, the head of pumping seawater, i.e. the altitude ofcarbon capture device, should be reduced to decrease the energyconsumption of pumping seawater. In an example of a large power plant,the carbon capture device, to which the scrubbing seawater is pumped, atan altitude of 50 m can meet the requirements. Of course, in otherexamples, 40 m, or 30 m can also meet the requirements. For some typicalapplications, such as power plants and marine ships, the followingexamples of the present application provide the detailed description. Inthese examples, carbon capture device, to which the scrubbing seawateris pumped, is configured at an altitude of no more than 20 m, or 19 m,or 15 m, or 12 m, or 10 m, or 9 m, or 8 m, or 6 m, or 5 m, or 4 m, or 2m, or 1 m. In another example, because the mean of tidal level in localarea at different time vary greatly, the carbon capture device is set ona platform or a floating dock and the platform or floating dock has anadjustable altitude according to level of tide. In such case, the energyconsumption of delivering seawater is reduced to the lowest levelaccording to the principle that boats go up with the level of the water.

On the other hand, the inventor also found in test that, among all kindsof scrubbing apparatus, packing scrubber or absorption tower as thecarbon capture device, is the best one for reducing amount of scrubbingseawater and reducing the head of pumping seawater. As a result, theenergy consumption of pumping seawater is the lowest, and the operatingis the most stable. Based on the long-termed experience of being engagedin desulfurization of seawater scrubbing and the test for absorption ofcarbon dioxide, the inventor of the present invention also found thatthe preferred dry packing factor of the packings is 5˜2000/m (thedefinition of dry packing factor can be found in manual of conventionalpacking industrial products). Such packings provide the best effect ofcarbon capture through seawater scrubbing. For example, packings of 5/mof dry packing factor can meet the requirements. In the followingexamples, the packing of 10/m, or 15/m, or 35/m, or 55/m, or 65/m, or95/m, or 150/m, or 250/m, or 350/m, or 450/m, or 650/m, or 850/m, or1000/m, or 1200/m, or 1500/m, or 1800/m, or 2000/m of dry packing factorcan also meet the requirements. The packing scrubbing refers to thescrubbings which is performed by the large area contact between thescrubbing seawater and the discharged flue gas in the packings.

According to the above description, the inventor of the presentinvention found that the energy consumption of carbon capture is reducedfinally and the total cost of CCS technology is reduced to a practicallevel through the strategies including packing scrubbing and reducingthe head of pumping seawater. For example, in an example, the energyconsumption of carbon dioxide capture is no more than 1000 MJ/t (millionjoule/ton), which is practical. For the applications of the power plantand marine ships, the following examples show that the energyconsumption of carbon capture is no more than 500 MJ/t, or 400 MJ/t, or350 MJ/t, or 300 MJ/t, or 250 MJ/t, or 200 MJ/t, or 150 MJ/t, or 100MJ/t, or 60 MJ/t, or 50 MJ/t, or 40 MJ/t, or 30 MJ/t, or 20 MJ/t, or 10MJ/t, or 5 MJ/t, which is also practical.

The inventor of the present invention further found that the carboncapture and storage can be used for the air in its natural state (DAC)on the sea according to the present invention, which has a good effectof reducing carbon content in the atmosphere. In the following examples,what are only used are the mechanical energy and/or electrical energycoming from the wind on the sea, and/or ocean current waves, and/orsunlight and other natural energy, which are all renewable energy. Itmeans that the energy consumption is zero. Therefore, the running costis very low and only construction and depreciation costs are requiredand electric power generation and transport and peripheral supports arenot needed. Moreover, the construction cost is also very low. On theother hand, the purpose of building a lot of wind driven and wave drivengeneration facilities is to replace the offshore fossil energy to reducethe atmosphere carbon emissions finally. However, the carbon dioxide inthe atmosphere can be captured and kept in storage directly according tothe present invention. In this case, the efficiency of reducing carbonis higher.

Further detailed description of the present invention is provided in thefollowing examples according to the drawings.

Example 1

This is a basic example of the process of ocean carbon capture andstorage of the present invention. As shown in FIG. 1 , the processincludes the steps of: 1) carbon capture including scrubbing gascontaining carbon dioxide with pumped seawater to produceafter-scrubbing seawater as a product of carbon capture in which thecarbon dioxide in the gas is absorbed; and 2) carbon storage includingdischarging the product of carbon capture into the water column of oceanto realize ocean storage.

In a varied example based on this example, in step 2), the product ofcarbon capture is discharged into the water column of ocean underatmospheric pressure through a pipe. The whole course from the carboncapture to the carbon storage is a consecutive reaction.

In another varied example based on this example, the process furthercomprises adjusting a ratio of volume of the seawater to volume ofcarbon dioxide in the product of carbon capture to adjust pH value ofthe product of carbon capture discharged into the ocean.

In another varied example based on this example, the process furthercomprises discharging the product of carbon capture into an oceancurrent in the water column of ocean that does not pass the locationwhere the scrubbing seawater is pumped.

In following varied examples based on this example, the process furthercomprises discharging the product of carbon capture into the surfacelayer, and/or the middle layer, and/or the deep layer of the watercolumn of ocean.

Example 2

This is another basic example of the process of ocean carbon capture andstorage of the present invention. As shown in FIG. 2 , the gascontaining carbon dioxide is the flue gas discharged from the burning offossil fuel and the process includes the steps of: a. continuouslyleading flue gas containing carbon dioxide which is discharged from aburner for burning fossil fuel into a carbon capture device; b.continuously leading seawater into the carbon capture device; c.providing packings in the carbon capture device to enlarge contact areaof the flue gas of step a and the seawater of step b to enhanceabsorbance of the carbon dioxide by the seawater; d. continuouslydischarging scrubbed flue gas into atmosphere; e. continuouslydischarging the seawater containing carbon dioxide generated in step cfrom the carbon capture device; and f. continuously discharging theseawater containing carbon dioxide generated in step e into a carboncapture location in the water column of ocean to realize the carbonstorage; wherein the fossil fuel is selected from a group consisting ofcoal, oil and gas; and the burner is selected from a group consisting ofa boiler of a steam turbine, an internal combustion engine and a gasturbine which are used in a coastal power plant or a marine ship; andthe flue gas is generated from burning of the fossil fuel; and theseawater of step b is the seawater pumped from an ocean to be used forscrubbing directly, and/or is the seawater pumped from an ocean to coolthe burner firstly before being used for scrubbing.

Example 3

This is an example based on above Example 2. As shown in FIG. 2 , atleast 10% of carbon dioxide in the flue gas in step a is removedcompared with the scrubbed flue gas in step d.

In a varied example based on this example, at least 20% of carbondioxide in the flue gas in step a is removed compared with the scrubbedflue gas in step d.

In more varied examples based on this example, at least 30%, or 40%, or50%, 60%, or 70%, or 80%, or 90% of carbon dioxide in the flue gas instep a is removed compared with the scrubbed flue gas in step d.

Example 4

This is an example based on Example 2. The difference between thedecreased pH value of the seawater containing carbon dioxide dischargedcontinuously in step e and the pH value of the seawater at thedischarging location, is on more than 2 pH unit. This pH value isachieved through configuring the volume of flue gas which is led intothe carbon capture device, the volume of scrubbing seawater and ratio ofgas to liquid. The purpose is to comply with the relevant laws andtechnical standards for marine drainage.

Example 5

This is a basic example of the apparatus of ocean capture and storagefor carrying out the process of the present invention. As shown in FIG.3 , the apparatus includes:

-   -   a burner 1 for producing the flue gas from the burning of fossil        fuel;    -   a carbon capture device 2, which is connected to the burner to        scrub the flue gas to capture carbon dioxide;    -   a seawater pumping equipment 3 for leading seawater into the        carbon capture device 2;    -   a chimney 6 for leading cleaned flue gas out of the carbon        capture device 2; and    -   a seawater discharging pipe 7.    -   Wherein, the carbon capture device 2 comprises a water        distributor 2.1. A packing layer is provided in the carbon        capture device 2.    -   A seawater outlet 5 of the carbon capture device 2 is connected        to the discharging pipe 7; and an outlet of the discharging pipe        7 is located in the water column of ocean.

Example 6

This is an example based on Example 5. The carbon capture device 2comprises the water distributor 2.1. The altitude 2.2 of the waterdistributor is not more than 20 m, and the altitude 2.2 of the waterdistributor is defined by a distance between a horizontal centre of thewater distributor 2.1 and level of ocean 3.2 where the scrubbingseawater is pumped into the seawater pumping equipment 3.

In more varied examples based on this example, the altitude 2.2 of thewater distributor is not more than 19 m, 15 m, 12 m, 10 m, 9 m, 8 m, 6m, 5 m, 4 m, 2 m, 1 m.

The purpose of reducing the altitude 2.2 of the water distributor is toreduce the energy consumption of delivering seawater. This energyconsumption is the main energy consumption of the CCS technology in thepresent invention.

The packing layer is provided in the carbon capture device 2. Thepacking layer is composed of industrial bulk packings, and the drypacking factor of the packings is 5/m.

In one varied example based on this example, the dry packing factor ofthe packings is 30/m.

In several other varied example based on this example, the dry packingfactor of the packings is 60/m, 120/m, 200/m, 300/m, 400/m, 500/m,600/m, 700/m, 800/m, 900/m, 1000/m, 1200/m, 1400/m. 1600/m, 1800/m,2000/m respectively.

In a varied example based on this example, the packing layer is composedof regular packings. In another varied example based on this example,the packing layer is composed of perforated plate packings.

In a varied example based on this example, the packing layer is composedof the combination of various packings.

Example 7

This is an example based on Example 5. As shown in FIG. 4 , Seawaterpumping equipment 3 connected to carbon capture device 2 is the seawatercooling system for burner 1.

In a varied example based on this example, seawater pumping equipment 3is the seawater increase pump 3.1.

In another varied example based on this example, seawater pumpingequipment 3 is the seawater cooling system for the burner 1 and theseawater increase pump 3.1. The purpose of such configuration is toprovide a greater amount of water to reduce emissions of carbon dioxide.

Example 8

This is an example of coastal gas-steam combined cycle power plant. Asshown in FIG. 3 , there are three sets of gas-steam combined cyclegenerating units in the plant. Power of each generating unit is 400 MW,and the total power is 1200 MW. There are two phases of implementationin this example.

In the first phase of implementation, carbon dioxide in flue gas of onegenerating unit is captured. At least 90% of the carbon dioxide in theflue gas is captured to be dissolved into the scrubbing seawater and isdischarged into the water column of ocean. About 1 million tons ofcarbon dioxide is captured and kept in storage per year.

A project of high concentration carbon capture and storage has beenperformed in this plant previously. In the project, carbon dioxide influe gas of one generating unit is captured. About 1 million tons ofcarbon dioxide is captured and kept in storage per year. The process ofthe project includes the steps of absorption, desorption, purification,compression and transportation of carbon dioxide. The captured carbondioxide of high concentration is injected into submarine oil field forEnhanced Oil Recovery (EOR). A special platform is provided in theocean. The project belongs to the submarine geological storage. Afterthe project is completed, although Enhanced Oil Recovery can bring acertain income and the total cost of the project is lower than that ofother non EOR CCS, the total cost is still unaffordable. Therefore, theproject was finally terminated.

The carbon capture device of the present example is installed in anempty space prepared for previous CCS project. The area needed by thecarbon capture device is only a fifth of the area of previous space. Thealtitude of water distributor of carbon capture device is about 10 m.Existing seawater cooling system is used directly as seawater leadingequipment. The existing inlet and outlet for cooling water in the plantare also used directly, and the depth of the outlet in the water columnis more than 150 m. In the coastal plant, for the purpose of coolingefficiency, outlet for cooling water is originally located in the watercolumn of the ocean where the ocean current does not pass the inlet forcooling water. In this case, after the carbon dioxide captured throughscrubbing is discharged, the carbon dioxide is diffused and dilutedrapidly with the ocean current, which further lessen the original tinyimpact on marine environment. The energy consumption of capturing carbondioxide is not more than 100 MJ/t, and the cost for building andoperating the CCS devices is 1/10 of the original cost of project ofhigh concentration.

In the second phase of implementation, more carbon capture devices andseawater pumps are added on the basis of the first phase ofimplementation, in order to perform the seawater scrubbing carboncapture and ocean water column carbon storage for other two generatingunits. After the completion of the second phase of implementation, about3 million tons of carbon dioxide is captured and kept in storage in theplant.

In one varied example based on this example, the carbon capture deviceis set on a platform that has an adjustable height according to level oftide. In another varied example based on this example, the carboncapture device is set on a floating dock. Thus the energy consumptionfor pumping seawater can be the lowest regardless of flux and reflux.

Example 9

This is an example of coastal coal power plants. As shown in FIG. 4 ,the burner is a 600 MW coal-fired generating unit. There are two phasesof implementation in this example.

In the first phase of implementation, at least 25% of carbon dioxide inthe flue gas of generating unit is captured to be dissolved into thescrubbing seawater. 70,000 t/h of cooling water in the plant is used asthe scrubbing seawater directly. About 800 thousand tons of carbondioxide is captured and kept in storage per year.

In the second phase of implementation, about 95% of carbon dioxide inthe flue gas of generating unit is captured to be dissolved into thescrubbing seawater. 210,000 t/h of scrubbing seawater is added. Theseawater is delivered through added seawater leading pumps. After thecompletion of the second phase of implementation, about 3 million tonsof carbon dioxide is captured and kept in storage for the generatingunit.

Packing tower is used in the carbon capture device to reduce thealtitude, and the altitude of the water distributor is about 9 m.Organic braided membrane water pipes are used to discharge the seawaterto the middle layer of the water column in the sea, which is about 300 mdepth of the water volume, to realize the ocean carbon storage.

In the present example, CO₂ emission of the flue gas of the power plantis reduced by 80%. The energy consumption for capturing carbon dioxideis not more than 200 MJ/t.

Example 10

This example is shown in FIG. 4 . A seawater adjusting pump 4 isconnected to a water regulator to adjust the pH value of the scrubbingseawater discharged into the ocean. This is a better way to control thepH value of discharged seawater and the energy consumption is thelowest.

The after-scrubbing seawater containing carbon dioxide is dischargedinto a layer between the surface level and the sea bed, which is the 800m depth of middle layer of the water column in the ocean.

In a varied example based on this example, the after-scrubbing seawatercontaining carbon dioxide is discharged into 1500 m depth of deep layerof the water column in the ocean. Studies indicated that: carbon dioxidecan be kept in storage for more than a thousand years if the carbondioxide is discharged into more than a thousand meters depth in theocean.

Example 11

This is an example of a marine ship. As shown in FIG. 5 , the burner 1includes a two-stroke ship diesel engine with 130 MW. Heavy oil ofsulfur 3.5% v-v is used as the fuel. The volume of generated CO₂ isabout 8100 Nm³/h. The carbon capture device is configured to substitutethe original muffler. The altitude of the water distributor is 6 m basedon the load waterline. The volume of scrubbing seawater for carboncapture and storage is about 5800 t/h. Seawater increase pump 3.1 can beadjusted to control the pH value of discharged seawater. In the presentexample, CO₂ emission of the ship flue gas is reduced by 50˜70%(specific value is related to the quality and temperature of theseawater where the ship sails), and SO₂ emission is reduced by 98%. Theeffect is equivalent to use of 0.5% S fuel. Therefore, the existing oilwith low cost can be still used after 2020 when the limitation to sulfurin global shipping will be performed by the United Nations. The energyconsumption of capturing carbon dioxide is not more than 20 MJ/t. Thecost for the whole process is equivalent to 0.6% of the fuel consumptionof the engine in full power. The discharging of seawater complies withthe rules of MEPC in MARPOL annex VI. The after-scrubbing seawater isdischarged into the surface layer of the water column in the ocean.

In this example, the detection and control of pH value of seawater inthe inlet and outlet is provided, which complies with the rules of MEPCin MARPOL annex VI. The flue gas of engine is scrubbed with seawater inthe running ship and no chemical agent is added. The difference of pHvalue between discharged scrubbing seawater and the seawater in inlet isno more than 2 pH unit. Therefore, the scrubbing seawater can bedischarged into the ocean directly, i.e. into the surface layer of watercolumn of the ocean.

In a varied example of building a new ship based on this example, thefuel of the ship is LNG. In this case, the carbon emissions are lessthan the emission from coal and oil, but it is still a kind of fossilenergy needed to reduce and control the carbon emissions.

Example 12

This is an example of apparatus of carbon direct air capture (DAC) andstorage on the sea. As shown in FIG. 6 , the apparatus comprises:

-   -   a carbon capture device 2;    -   a seawater pumping equipment 3 for leading seawater into the        carbon capture device 2;    -   a power equipment 14 for providing power for the seawater        pumping equipment 3;    -   a water distributor 2.1 which is over the carbon capture device        2;    -   a water collector 2.3 which is under the carbon capture device        2; and    -   a water discharging pipe 7 which is connected to the water        collector 2.3.

The apparatus is fixed on a platform floating on the ocean. The platformis anchored to the seabed.

In a varied example based on this example, the apparatus is fixed on anocean platform which is connected to the seabed rigidly. In anotherexample based on this example, the apparatus is fixed on an oceanmoveable platform.

Example 13

This is an example based on Example 12. As show in FIG. 6 , the powerequipment 14 comprises:

-   -   a water driven device 14.2;    -   a power transmission device 14.3 which is connected to the        seawater pumping equipment 3 to transmit the power provided by        the water driven device 14.2 to the seawater pumping equipment        3, wherein the power transmission device 14.3 is a mechanical        transmission device.

In a varied example based on this example, the power transmission device14.3 is an electromechanical transmission device composed of a waterdriven generator and electromotor.

Example 14

This is another example based on Example 12. As show in FIG. 7 , thepower equipment 14 comprises:

-   -   a wind driven device 14.1;    -   a power transmission device 14.3 which is connected to the        seawater pumping equipment 3 to transmit the power provided by        the wind driven device 14.1 to the seawater pumping equipment 3,        wherein the power transmission device 14.3 is a mechanical        transmission device.

In this example, a water discharging pipe 7 is connected to the watercollector 2.3 under the carbon capture device 2. The outlet of the waterdischarging pipe 7 is located in the water column of an ocean todischarge the scrubbing seawater containing carbon dioxide into theocean. Vertical axis rotor is used in the wind driven device.Alternatively, horizontal axis rotor can also be used. The wind drivendevice transforms the captured wind energy into the rotating mechanicalenergy to drive the seawater pumping equipment to pump seawaterdirectly. The effect of scrubbing the captured carbon dioxide will bebetter if the seawater in deeper layer of ocean is pumped. If the waterlever in the water collector under the carbon capture device drives thescrubbing seawater into the deeper layer of ocean, the effect of carbonstorage will be better. The power transmission device 14.3 has afunction of mechanical speed regulation. The carbon capture device 2 isdesigned to be open vertically to be helpful for capturing the wind. Thepackings composed of grid plates and grids are provided to improve theefficiency of scrubbing.

In a varied example based on this example, hollow spray tower is used asthe carbon capture device. In another varied example based on thisexample, conventional washing tower is used as the carbon capturedevice. In another varied example based on this example, the scrubbingseawater is not collected by the water collector but sprayed on thesurface of ocean directly.

In another varied example based on this example, a blower is used toblow air in the carbon capture device. The power of blower comes fromthe wind driven device too.

The apparatuses in the above example are kind of carbon reductionwindmill apparatuses. The manufacturing and maintaining cost of theapparatus is far lower than the one of wind driven generator with thesame rotor diameter. The effect of reducing the atmospheric carboncontent of the apparatus is many times the one of the latter becausemultistage energy conversion is not required.

Example 15

This is another example based on Example 12. The power equipment 14comprises:

-   -   a wind driven device 14.1;    -   a power transmission device 14.3;        wherein the power transmission device 14.3 is an        electromechanical transmission device composed of a water driven        generator and electromotor. Offshore wind driven generator is        used as the power equipment 14 directly.

In a varied example based on this example, solar power equipments areused as the power equipment 14 directly.

The protection scope of the claim of the present invention is notlimited to the above examples.

The invention claimed is:
 1. An apparatus of ocean carbon capture andstorage, comprising: a carbon capture device for scrubbing gascontaining carbon dioxide to capture carbon dioxide; a seawater pumpingequipment for pumping seawater and leading the seawater into the carboncapture device; and a seawater discharging pipe for discharging theseawater from the carbon capture device into a water column of ocean torealize ocean storage; wherein the apparatus further comprises: a powerequipment for providing power for the seawater pumping equipment; awater distributor which is over the carbon capture device; and a watercollector which is under the carbon capture device; wherein the seawaterdischarging pipe is connected to the water collector.
 2. The apparatusof claim 1, wherein the apparatus is configured to carry out a processof ocean carbon capture and storage, the process comprising steps of: 1)Carbon capture including scrubbing gas containing carbon dioxide withpumped seawater to produce after-scrubbing seawater as a product ofcarbon capture in which the carbon dioxide of the gas is absorbed; and2) Carbon storage including discharging the product of carbon captureinto the water column of ocean to realize ocean storage.
 3. Theapparatus of claim 2, wherein in step 2), the product of carbon captureis discharged into the water column of ocean under atmospheric pressurethrough a pipe.
 4. The apparatus of claim 2, wherein the process furthercomprises adjusting a ratio of volume of the seawater to volume ofcarbon dioxide in the product of carbon capture to adjust pH value ofthe product of carbon capture discharged into the ocean.
 5. Theapparatus of claim 2, wherein the gas containing carbon dioxide instep 1) is atmosphere.
 6. The apparatus of claim 2, wherein the gascontaining carbon dioxide is flue gas discharged from burning of fossilfuel.
 7. The apparatus of claim 1, wherein the seawater pumpingequipment is configured to use power provided by wind, and/or wave ofocean current, and/or sunlight.
 8. The apparatus of claim 1, wherein thecarbon capture device is located on an ocean platform which has anadjustable altitude according to level of tide.
 9. The apparatus ofclaim 6, wherein the process further comprises the steps that at least10%, or 20%, or 50%, or 70%, or 80%, or 90% of the carbon dioxide in theflue gas is absorbed into the scrubbing seawater and then is dischargedinto the water column of ocean, and a volume of the scrubbing seawateris configured to be enough to absorb at least 10%, or 20%, or 50%, or70%, or 80%, or 90% of the carbon dioxide of the flue gas.
 10. Theapparatus of claim 6, wherein the process further comprises the stepthat the seawater is pumped to a head of no more than 50 m, or 40 m, or30 m, or 20 m, or 19 m, or 15 m, or 12 m, or 10 m, or 9 m, or 8 m, or 6m, or 5 m, or 4 m, or 2 m, or 1 m to scrub the flue gas containingcarbon dioxide, wherein the head of 0 m is a level of ocean where thescrubbing seawater is pumped.
 11. The apparatus of claim 6, wherein theprocess further comprises providing packings and performing thescrubbing in the packings and configuring a head of the pumped scrubbingseawater so that an energy consumption of the carbon capture is no morethan 1000 MJ/t, or 500 MJ/t, or 400 MJ/t, or 350 MJ/t, or 300 MJ/t, or250 MJ/t, or 200 MJ/t, or 150 MJ/t, or 100 MJ/t, or 60 MJ/t, or 50 MJ/t,or 40 MJ/t, or 30 MJ/t, or 20 MJ/t, or 10 MJ/t, or 5 MJ/t.
 12. Theapparatus of claim 1, wherein the apparatus further comprises: a burnerfor producing flue gas from burning of fossil fuel; and a chimney forleading cleaned flue gas out of the carbon capture device; wherein thecarbon capture device is connected to the burner, the carbon capturedevice comprises a water distributor and a packing layer; and a seawateroutlet of the carbon capture device is connected to the seawaterdischarging pipe; and an outlet of the discharging pipe is located inthe water column of ocean.
 13. The apparatus of claim 12, wherein analtitude of the water distributor of the carbon capture device isconfigured to be no more than 50 m, or 40 m, or 30 m, or 20 m, or 19 m,or 15 m, or 12 m, or 10 m, or 9 m, or 8 m, or 6 m, or 5 m, or 4 m, or 2m, or 1 m, wherein the altitude of the water distributor is defined by adistance between a horizontal centre of the water distributor and levelof ocean where scrubbing seawater is pumped into the seawater pumpingequipment.
 14. The apparatus of claim 12, wherein the apparatus furthercomprises a seawater adjusting pump which is connected to a waterregulator to adjust pH value of scrubbing seawater discharged into theocean.
 15. The apparatus of claim 12, wherein the packing layer of thecarbon capture device is composed of industrial bulk packings, and/orregular packings, and/or perforated plate packings, and/or grilles. 16.The apparatus of claim 1, wherein the power equipment comprises: a winddriven device; a power transmission device which is connected to theseawater pumping equipment to transmit the power provided by the winddriven device to the seawater pumping equipment; wherein the powertransmission device comprises a mechanical transmission device and/or aelectromechanical transmission device composed of a wind drivengenerator and an electromotor.
 17. The apparatus of claim 1, wherein thepower equipment comprises: a water driven device; a power transmissiondevice which is connected to the seawater pumping equipment to transmitthe power provided by the water driven device to the seawater pumpingequipment; wherein the power transmission device comprises a mechanicaltransferring device and/or an electromechanical transmission devicecomposed of a water driven generator and electromotor.
 18. A coastalpower plant comprising the apparatus of claim
 1. 19. A marine shipcomprising the apparatus of claim 1.